Silent chains are used as a timing chain in automobiles, motorcycles, and the like. The silent chain generally has a configuration in which a large number of link plates comprising respective pairs of tooth parts and pin holes are respectively coupled in a pivotable manner by connecting pins which are inserted into each pin hole, and also guide plates are arranged on the outermost side.
Furthermore, a chain guide for guiding the chain during travel of the chain is arranged on the tight side span of the silent chain, and a tensioner arm for maintaining suitable tension by removing slack in the chain is arranged on the slack side span. A pair of guide parts (or side wall parts) which are arranged on both sides of the chain in the width direction during travel of the chain are provided on the chain sliding surfaces of the chain guide and tension arm (see Japanese Unexamined Patent Application Publication H8-303541 and Japanese Unexamined Patent Application Publication 2006-112447).
During operation of the silent chain, the silent chain slides on and travels along the sliding surfaces of the chain guide and the tension arm, and at this time the outer side surfaces of the guide plates of the silent chain come into sliding contact with the guide parts of the chain guide and tension arm.
Accordingly, in conventional silent chains, the outer side surfaces of the guide plates come into sliding contact with the guide parts of the chain guide and tension arm during travel of the chain, whereby friction loss is generated.
On the other hand, there has been a strong demand for improved fuel consumption in the recent automobile industry in the light of saving climate. As a result, in the timing chains as well, improvements have been required in order to reduce a friction loss during travel.
The present invention has been made in view of such conventional circumstances and the problem which the present invention aims to resolve is to provide a silent chain which can reduce a friction loss during travel.